1. Field of the Invention
The present invention relates generally to joints for locking first and second components, and in particular to supporting an agricultural implement stack fold toolbar in a folded position for transportation.
2. Description of the Related Art
Implements and equipment for tillage, cultivation and other agricultural operations have been developed with the objectives of increasing efficiency and lowering operating costs. For example, wider equipment tends to be more efficient because greater field areas can be covered with fewer passes in less time. Tractors have tended to become larger in order to accommodate such wider implements and their greater towing power requirements.
Modern agricultural operations commonly require equipment adapted for transporting over public roads. For example, many farmers and farming operations work multiple, noncontiguous fields with the same equipment, which must be configured to comply with traffic regulations, including maximum width requirements. Various implement folding mechanisms have been developed for this purpose. For example, implements are commonly designed with movable sections, which can swing towards the front or the rear in order to reduce the overall implement widths. Implements are also available with wing sections adapted for folding upwardly to overhead positions for transport. General design objectives for folding implements include safety, convenience and efficiency with folding and transporting operations.
A problem associated with previous folding implements relates to structural stresses and loads encountered in transit over public roads. Folding them for transport tends to change their centers of gravity and relocate wheels and other structures that provide support during field operations. For example, implements with outer sections that fold upwardly have higher centers of gravity in their transport than in their working positions, which can affect stability in over-the-road travel. Uneven road surfaces can cause such implements to sway in transit, with resulting wear, stress and possible damage.
Another folding implement design consideration involves toolbar orientation. For example, toolbars equipped with planters are preferably kept level throughout the implement folding sequence in order to avoid spilling the contents of their seed hoppers. The “stack fold” mechanism was developed to keep the wing sections generally level by means of a parallelogram-type geometry. The outboard or wing toolbar sections of a stack fold implement swing upwardly and inwardly from working positions aligned with a center toolbar section to folded, horizontal transport positions located above and generally parallel with the center section. The wing sections remain generally horizontal and level throughout the stack folding sequence. An example of this type of implement folding mechanism is shown in the Moore U.S. Pat. No. 6,003,615. Stack folding implements have folded transport positions that are relatively compact for transportation over public roads and storage. Moreover, seed can be left in the planter hoppers when the wing sections on which they are mounted are lifted and stacked.
Previous stack fold mechanisms located the folded wing sections in spaced relation from each other, thereby allowing them to move independently. However, such independent wing section movements during transit can subject their frames and hydraulics to excessive wear and stress. Such stresses are greater when planters and other tools add to the overall weight of the elevated wing sections. The dynamic loads associated with prior art stack fold implements in their folded, transport positions tend to be exerted against the pivot joints and the hydraulic piston-and-cylinder units, with potentially adverse consequences. The folded wing sections of such prior art stack fold implements were typically independent of each other, and were thus free to move without mutual restraint. The present invention addresses these considerations. Heretofore there is not been available a transport lock joint for stack fold toolbars with the advantages and features of the present invention.